Your post has approximately 19 thousands questions, so I’m definitely not too keen on answering to every single one. 
Don’t worry about tangential concerns, tackle the main problem first - there will be more than plenty things to do.
Just search online for how location is managed in web apps, without focusing on ClojureScript. It will be some JS code that calls into some browser API - simply do the same thing in CLJS, only via JS interop. Any kind of pattern, any kind of relevant approach used with JS can be used in CLJS as well via interop.